Blood eosinophils as a marker of likely corticosteroid response in children with preschool wheeze: time for an eosinophil guided clinical trial?

Risk factors for recurrent wheezing after bronchiolitis

BACKGROUND

This study aimed to determine whether there was an association between certain factors in patients with bronchiolitis and recurrent wheezing in childhood.

METHOD

In 2021 we tracked children hospitalized for bronchiolitis at Chengdu Women's and Children's Central Hospital in 2017. The patients were classified into recurrent wheezing group (RWG) and non-recurrent wheezing group (NRWG). Possible risk factors including maternal age, school-age siblings, allergic history, atopic dermatitis, allergic rhinitis, atopic family history, severity of the condition, duration of hospitalization, nasopharyngeal secretions culture, blood eosinophil counts, FeNO and skin prick test were compared between the two groups. Continuous variables were analyzed by independent sample t-test for normal distribution and Mann-Whitney U-test for non-normal distribution. Categorical variables were tested using chi-square tests. Multifactor analysis was conducted by stepwise logistics regression analysis.

RESULTS

In total 167 participants were included, of which 26 and 141 were in RWG and NRWG respectively. In RWG children represented higher maternal age (P = 0.02) and greater probability of allergic history, atopic dermatitis, allergic rhinitis, atopic family history (odds ratio [OR] = 4.0,3.7, 7.8, 10.9 respectively, P < 0.01). However, school-age siblings, severity of the condition, duration of hospitalization, blood eosinophil counts, fractional exhaled nitric oxide and skin prick test results seemed unrelated to recurrent wheezing. In the subgroup analysis of nasopharyngeal secretion culture, there were more Moraxella catarrhalis-positive in RWG(P = 0.043). Atopic dermatitis, allergic rhinitis and atopic family history were identified as independent risk factors for recurrent wheezing.

CONCLUSION

Some children with bronchiolitis will develop recurrent wheezing, and the risk factors are allergic history, Moraxella catarrhalis infection or colonization, atopic dermatitis, allergic rhinitis and atopic family history; the latter three are independent risk factors.

Utility of biomarkers in the diagnosis and monitoring of asthmatic children

Asthma imposes a heavy morbidity burden during childhood; it affects over 10% of children in Europe and North America and it is estimated to exceed 400 million people worldwide by the year 2025. In clinical practice, diagnosis of asthma in children is mostly based on clinical criteria; nevertheless, assessment of both physiological and pathological processes through biomarkers, support asthma diagnosis, aid monitoring, and further lead to better treatment outcomes and reduced morbidity. Recently, identification and validation of biomarkers in pediatric asthma has emerged as a top priority across leading experts, researchers, and clinicians. Moreover, the implementation of non-invasive biomarkers for the assessment and monitoring of paediatric patients with asthma, has been prioritized; however, only a proportion of them are currently included in the clinical practise. Although, the use of non-invasive biomarkers is highly supported in recent asthma guidelines for documenting diagnosis and supporting monitoring of asthmatic patients, data on the Pediatric population are limited. In the present report, the Pediatric Asthma Committee of the World Allergy Organization (WAO), aims to summarize and discuss available data for the implementation of non-invasive biomarkers in the diagnosis and monitoring in children with asthma. Information on the most studied biomarkers, including spirometry, oscillometry, markers of allergic sensitization, fractional exhaled nitric oxide, and the most recent exhaled breath markers and "omic" approaches, will be reviewed. Practical limitations and considerations based on both experts' opinion and critical review of the literature, on the utility of all "well-known" and newly introduced non-invasive biomarkers will be presented. A critical commentary on biomarkers' use in diagnosing and monitoring asthma during the COVID-19 pandemic, cost and availability of biomarkers in different settings and in developing countries, the differences on the biomarkers use between Primary Practitioners, Pediatricians, and Specialists and their role on the longitudinal aspect of asthma is provided.

Association of increased basic salivary proline-rich protein 1 levels in induced sputum with type 2-high asthma

BACKGROUND

The aim of this study is to reveal whether basic salivary proline-rich protein BstNI subfamily 1 (PRB1) may be used as a diagnostic biomarker for type 2-high asthma.

METHODS

PRB1 protein levels in the induced sputum of 67 subjects with asthma and 27 controls were determined by an enzyme-linked immunosorbent assay. Correlation analyses between PRB1 in the induced sputum and airway inflammatory indicators were also performed.

RESULTS

PRB1 protein levels were significantly upregulated in the induced sputum of asthmatic patients (p =0.0098) and correlated with clinical eosinophil-related indicators and type 2 airway inflammation. These results indicate that PRB1 is a promising biomarker for type 2-high asthma.

CONCLUSIONS

The expression of PRB1 in induced sputum is a potential biomarker for type 2-high asthma. The results of this study present new insights into the diagnosis and treatment of asthma.

Precision Medicine for Paediatric Severe Asthma: Current Status and Future Direction

Asthma is a heterogeneous disease, characterised by different phenotypes and endotypes. Precision medicine in asthma refers to the implementation of a targeted therapy for each individual child, based on the identification of treatable traits, including environmental, immunological and genetic factors. Severe asthma in children is associated with increased hospitalisation rates, a lower quality of life, increased healthcare costs and an increased mortality. In the era of new molecular biologics treatments, it is essential to improve deep phenotyping of children with severe asthma in order to deliver the most effective treatment to each individual child. In this review, we discuss the personalised approach to the assessment and management of severe asthma. We explore the indications and use of the currently licensed biologics, as well as the potential of other emerging treatments.

Assessing the feasibility and acceptability of online measurements of exhaled volatile organic compounds (VOCs) in children with preschool wheeze: a pilot study

BACKGROUND

Investigating airway inflammation and pathology in wheezy preschool children is both technically and ethically challenging. Identifying and validating non-invasive tests would be a huge clinical advance. Real-time analysis of exhaled volatile organic compounds (VOCs) in adults is established, however, the feasibility of this non-invasive method in young children remains undetermined.

AIM

To determine the feasibility and acceptability of obtaining breath samples from preschool children by means of real-time mass spectrometry analysis of exhaled VOCs.

METHODS

Breath samples from preschool children were collected and analysed in real time by proton transfer reaction-time of flight-mass spectrometry (PTR-TOF-MS) capturing unique breath profiles. Acetone (mass channel m/z 59) was used as a reference profile to investigate the breath cycle in more detail. Dynamic time warping (DTW) was used to compare VOC profiles from adult breath to those we obtained in preschool children.

RESULTS

16 children were recruited in the study, of which eight had acute doctor-diagnosed wheeze (mean (range) age 3.2 (1.9-4.5) years) and eight had no history of wheezing (age 3.3 (2.2-4.1) years). Fully analysable samples were obtained in 11 (68%). DTW was used to ascertain the distance between the time series of mass channel m/z 59 (acetone) and the other 193 channels. Commonality of 12 channels (15, 31, 33, 41, 43, 51, 53, 55, 57, 60, 63 and 77) was established between adult and preschool child samples despite differences in the breathing patterns.

CONCLUSION

Real-time measurement of exhaled VOCs by means of PTR-MS is feasible and acceptable in preschool children. Commonality in VOC profiles was found between adult and preschool children.

Acute Severe Asthma in Adolescent and Adult Patients: Current Perspectives on Assessment and Management

Asthma is a chronic airway inflammatory disease that is associated with variable expiratory flow, variable respiratory symptoms, and exacerbations which sometimes require hospitalization or may be fatal. It is not only patients with severe and poorly controlled asthma that are at risk for an acute severe exacerbation, but this has also been observed in patients with otherwise mild or moderate asthma. This review discusses current aspects on the pathogenesis and pathophysiology of acute severe asthma exacerbations and provides the current perspectives on the management of acute severe asthma attacks in the emergency department and the intensive care unit.

Processing small sputum samples: a method validation study

Background: Eosinophilia is frequently a feature of asthma. Sputum analysis can help with the diagnosis and phenotyping of asthma. The current gold standard method is unsuitable for samples <100 mg. However, children frequently produce samples below this threshold.Aim: To compare and validate our modified, small sample (>10 mg and <100 mg) sputum processing method (which omits sample filtering), with the current gold standard. Method: Prospective study of 32 adults with severe asthma providing sputum samples of sufficient size for dual processing. Results: The median (IQR) sample weight was 211.0 (162.4-185.5) mg and 57.5 (22.0-61.6) mg for standard, and small sputum sample processing respectively. There was no statistically significant difference in the median (IQR) cell counts between Method A and B, respectively: eosinophils 3.8% (1.5-14.0) versus 4.9% (1.3-15.5); neutrophils 78.1% (46.5-92.4) versus 65.0% (48.3-86.6). Conclusion: The small sputum sample processing is feasible and reliable, and yields similar results to standard processing.

Eosinophil cell count in bronchoalveolar lavage fluid in early childhood wheezing: is it predictive of future asthma?

Objective: Increased eosinophil level in bronchoalveolar lavage fluid (BALF) characterizes asthma in school-age children and adults and has been suggested as a marker for disease severity and response to treatment. We aimed to investigate the occurrence and yield of BALF eosinophil cell count in preschool children with recurrent wheezing and its possible relation to future diagnosis of asthma. Methods: BALF was retrospectively studied in young wheezy children and its relation to asthma at age 6 years was evaluated. BALF from children aged 1-48 months (mean = 20.4) was analyzed in preschool wheezy children. Children with anatomical airway obstruction and other lower airway/lung diseases who underwent BALF served as controls. Assessment of asthma was accomplished at 6 years. Results: Eighty-two children were included. The mean age during bronchoscopy and BAL was 20.4 ± 14.4 months (range: 1-48 months). Twenty-six patients had recurrent preschool wheezing, 13 anatomical airway obstruction and 43 had other lower airways/lung diseases. Groups were comparable for age during bronchoscopy and gender. No difference was found between groups for any of the BALF cell types. Eosinophils were very low in all three groups [mean (interquartile range): 0 (0-0.4), 0 (0-0.8), and 0.4 (0-1), respectively, p = 0.25]. No difference in eosinophil levels during bronchoscopy was found between asthmatic children to non-asthmatic as defined at age 6 years. Conclusions: Wheezing in preschool children is not associated with increased BALF eosinophils; hence, at this age, the diagnostic yield of BALF for cell count analysis for diagnosing asthma is limited and is not routinely indicated.

Biomarkers for Recurrent Wheezing and Asthma in Preschool Children

Wheezing is one of the characteristic symptoms of asthma, but all preschool children with wheezing are not diagnosed with asthma. Preschool children are not cooperative enough to participate in spirometry and invasive tests. Thus, there is no conventional method to diagnose asthma in preschool children. We reviewed studies on non-invasive biomarkers for assessing asthma in preschool children. Specimens that can be easily obtained by non-invasive methods are blood, exhaled breath and urine. Eosinophils, eosinophil cationic protein and eosinophil-derived neurotoxin (EDN) in blood are helpful in evaluating eosinophilic inflammation of the airways. Exhaled breath contains nitric oxide, volatile organic compounds, various cytokines and mediators as analytical components. Fraction of exhaled nitric oxide has been used to assess the degree of eosinophil inflammation and has been standardized in school-age children and adults, but not yet in preschool children. Exhaled breath condensate (EBC) pH and various cytokines/mediators that are detected in EBC seem to be promising biomarkers for assessing asthma, but need more standardization and validation. There are several biomarkers useful for assessing asthma, but none are ideal. Some biomarkers need standardized methods of obtaining samples from uncooperative preschool children for clinical use and require sufficient validation. Recently, another activated eosinophil marker, serum EDN, has shown promising results as a biomarker for recurrent wheezing and asthma in preschool children.

The Role of FeNO in Predicting Asthma

Asthma-like symptoms like wheezing and dyspnea affect 1 in every 3 preschool children. An easily available biomarker that predicts later asthma or unfavorable lung growth in these children may be helpful in targeting the right child with the right drugs and avoiding exposure to potentially harmful drugs in others. The fraction of exhaled nitric oxide (FeNO) has been suggested as a marker of eosinophilic inflammation. FeNO can be measured in a standardized way from the age of 4 but several methods have been developed to measure FeNO also in younger children. Several studies have assessed the predictive value of FeNO in preschool wheezing children for asthma later in life. These studies have shown that FeNO may be helpful in defining different preschool wheezing phenotypes, and in assessing the risk of later asthma or impaired lung growth. However, data are conflicting on the added value over clinical parameters. In two studies in school children, high FeNO was predictive for asthma development during follow up and also predicted lower lung function growth. In school children with respiratory symptoms suggestive of asthma, particularly in atopic children, FeNO has diagnostic value for an asthma diagnosis, mostly for ruling in asthma. There are not enough data to assess if FeNO has a predictive value for lung development in school children.

Epithelial SERPINB10, a novel marker of airway eosinophilia in asthma, contributes to allergic airway inflammation

Serine peptidase inhibitor, clade B, member 10 (SERPINB10) expression is increased in IL-13-stimulated human bronchial epithelial cells and in a murine model of allergic airway inflammation. However, the role of SERPINB10 in asthma remains unknown. We examined the association between epithelial SERPINB10 expression and airway eosinophilia in subjects with asthma and the role of Serpinb10 in allergic airway inflammation in an animal model. Epithelial SERPINB10 mRNA and protein expression were markedly increased in subjects with asthma ( n = 60) compared with healthy controls ( n = 25). Epithelial SERPINB10 mRNA levels were significantly correlated with airway hyperresponsiveness (AHR) and three parameters reflecting airway eosinophilia including the percentage of sputum eosinophils, the number of eosinophils in bronchial submucosa, and fraction of exhaled nitric oxide in subjects with asthma. Moreover, epithelial SERPINB10 expression was strongly correlated with the epithelial gene signature ( CLCA1, POSTN, and SERPINB2) for type 2 status. In normal human bronchial epithelial cells cultured at air-liquid interface, knockdown of SERPINB10 suppressed IL-13-stimulated periostin (encoded by POSTN) and CCL26 (eotaxin-3) expression by inhibiting the activation of p38 MAPK. Epithelial CCL26 mRNA levels were correlated with SERPINB10 expression in subjects with asthma. Airway knockdown of Serpinb10 alleviated AHR, airway eosinophilia and the expression of periostin and Ccl26 in a murine model of allergic airway disease. Taken together, epithelial SERPINB10 is a novel marker for airway eosinophilia in asthma. Epithelial SERPINB10 contributes to allergic airway eosinophilic inflammation, at least in part, by regulating the expression of periostin and CCL26.

Preschool wheeze, genes and treatment

Preschool wheeze is a common but poorly understood cause of respiratory morbidity that is both distinct from and overlaps with infantile bronchiolitis and school age asthma. Attempts at classification by epidemiology, pathophysiology, therapeutic response and clinical phenotype are imperfect and yet fundamental to both treatment choice and research design. The four main therapeutic classes for preschool wheeze, namely beta₂ agonists, anticholinergics, corticosteroids and leukotriene modifiers are employed with variable and often scanty evidence base, with evidence for a genetic influence on response variations. The article will discuss the pharmacogenetics of the various options, summarise current treatment recommendations, and explore future research directions.

Precision medicine in asthma: linking phenotypes to targeted treatments

PURPOSE OF REVIEW

Asthma is a heterogeneous disease consisting of different phenotypes that are driven by different mechanistic pathways. The purpose of this review is to emphasize the important role of precision medicine in asthma management.

RECENT FINDINGS

Despite asthma heterogeneity, the approach to management has been on the basis of disease severity, with the most severe patients reserved for the maximum treatments with corticosteroids and bronchodilators. At the severe end, the recent availability of biologic therapies in the form of anti-IgE (omalizumab) and anti-IL5 therapies (mepolizumab and reslizumab) has driven the adaptation of precision medicine. These therapies are reserved for severe asthma with defined either allergic or eosinophilic background, respectively.

SUMMARY

Unbiased definition of phenotypes or endotypes (which are phenotypes defined by mechanisms) is an important step towards the use of precision medicine in asthma. Although T2-high asthma has been defined with targets becoming available for treating allergic or eosinophilic asthma, the definition of non-T2 phenotypes remains a priority. Precision medicine is also dependent on the definition of biomarkers that can help differentiate between these phenotypes and pinpoint patients suitable for specific-targeted therapies. Thus, precision medicine links phenotypes (endotypes) to targeted treatments for better outcomes.

Personalised medicine in asthma: time for action: Number 1 in the Series "Personalised medicine in respiratory diseases" Edited by Renaud Louis and Nicolas Roche

Asthma is a heterogeneous disease comprising several phenotypes driven by different pathways. To define these phenotypes or endotypes (phenotypes defined by mechanisms), an unbiased approach to clustering of various omics platforms will yield molecular phenotypes from which composite biomarkers can be obtained. Biomarkers can help differentiate between these phenotypes and pinpoint patients suitable for specific targeted therapies - the basis for personalised medicine. Biomarkers need to be linked to point-of-care biomarkers that may be measured readily in exhaled breath, blood or urine. The potential for using mobile healthcare approaches will help patient enpowerment, an essential tool for personalised medicine. Personalised medicine in asthma is not far off - it is already here, but we need more tools and implements to carry it out for the benefit of our patients.

The influence of inhaled corticosteroid discontinuation in children with well-controlled asthma

Asthma is a chronic inflammatory disease that requires adherence to both preventative and therapeutic interventions in disease management. Children with asthma are likely to discontinue inhaled corticosteroids (ICS), especially when symptoms are under control. We aimed to investigate the impact of ICS adherence in children whose symptoms were under control.The study is cohort study; 35 children with controlled asthma that had undergone 3 years of follow-up were included. Serum eosinophil count, serum total IgE (tIgE), and lung function (FEV1, FEV1/FVC, PEF, FEF20-75%, and PC20) were evaluated at the beginning and end of the follow-up.At baseline, patients in both the adherent and nonadherent groups were similar. After 3 years, the nonadherent group who had discontinued ICS had a decrease in FEV1 (P < .05), FEV1/FVC (P < .05), PEF (P < .05), and FEF20-75% (P < .05). The nonadherent group had no significant improvement in PC20 compared with their values at the beginning of the follow-up, whereas the adherent group had improvement in PC20. Furthermore, there was an increase in serum eosinophil (P < .001) and tIgE (P < .05) in the nonadherent compared with the adherent group.Despite good asthma control, airway hyperresponsiveness (AHR) was detected in a large proportion of children with asthma. ICS discontinuation affected lung function, serum eosinophil count, tIgE, and AHR. Adequate adherence is important in asthma management. The benefits of ICS and the influence of drug discontinuation despite good asthma control may encourage better adherence from patients.

Severe therapy resistant asthma in children: translational approaches to uncover sub-phenotypes

INTRODUCTION

Paediatric severe therapy resistant asthma (STRA) affects a very small proportion of all children with asthma, but results in significant morbidity, has a high risk of mortality and utilises approximately half of all healthcare resources for childhood asthma. children with STRA need add-on 'beyond guidelines' therapies because of poor control despite maximal conventional treatments and optimisation of basic asthma management. however, STRA is heterogeneous with marked phenotypic variation between patients and mechanisms from adult severe asthma cannot be extrapolated to children. Areas covered: This review will cover our current knowledge of paediatric STRA pathophysiology, with examples of translational approaches that have been used to define sub-phenotypes including; 1. pre-clinical age-appropriate models using clinically relevant allergens, 2. in vitro techniques incorporating complex co-cultures of structural and inflammatory cells, and 3. techniques that allow detailed cellular immunophenotyping of small airway samples will be discussed. Studies using these approaches that have demonstrated the importance of the innate mediator IL-33 and vitamin D deficiency in severe steroid resistant disease will also be discussed. Expert commentary: These experimental approaches allow investigation of age and disease specific molecular pathways and the development of personalised therapies that can be stratified and targeted to sub-phenotypes of paediatric STRA.

Asthma phenotypes in children and stratified pharmacological treatment regimens

INTRODUCTION

Asthma is the most common inflammatory disease in childhood. The interaction of genetic, environmental and host factors may contribute to the development of childhood asthma and defines its progress, including persistence and severity. Until now, various classifications of childhood asthma phenotypes have been suggested based on patient's age during onset of symptoms, type of inflammatory cells, response to treatment and disease severity. Many efforts have been carried out to identify childhood asthma phenotypes and to clarify which are the risk factors that define asthma prediction and the response to therapy. The identification of asthma phenotypes has not only prognostic but also therapeutic role. However, the classification of asthma phenotypes is complex due to the heterogeneity of the disease. Areas covered: The current childhood asthma phenotypes and the new therapeutic strategies for each phenotype are reviewed. Expert commentary: There are multiple phenotypes in childhood asthma and it is crucial to define them before the initiation of personalized treatment. Both the therapeutic strategy and monitoring should follow the recent guidelines.

Biomarkers for the Phenotyping and Monitoring of Asthma in Children

An important issue in relation to the utility and reliability of biomarkers for asthma monitoring is how asthma is defined and characterized. What kind of asthma, or at what stage of the disease is a particular biomarker supposed to add information? Often, the purpose, or usefulness of a biomarker is not made clear. Diagnosis, severity evaluation, and monitoring are all different clinical uses for a biomarker, and confusion may arise when a biomarker is suitable for one of these but not another. When the utility of available biomarkers are discussed, these different roles need to be clarified. Our opinion is that there are four aspects of relevance to asthma, for which biomarkers are required: to diagnose allergies, to evaluate inflammation in the airways, to evaluate hyper-responsiveness, and for certain measures of lung function, such as lung clearance index. These types of biomarkers are needed for the phenotyping and monitoring of asthma. Another important role for biomarkers is, as mentioned above, to monitor asthma in order to follow treatment effects on inflammation and hyper-responsiveness as objective adjuncts to the patients' own symptom reports and lung function. This review will mainly focus on biomarkers that reflect airway inflammation. In spite of the numerous studies that have been conducted, we still have to remember that the value of biomarkers available for routine use, such as eosinophil counts in blood and sputum and exhaled nitric oxide, have to be interpreted in relation to reported symptoms and lung function. Measures of bronchial hyper-responsiveness, performed either by direct (methacholine challenge) or indirect (exercise or mannitol challenge) methods, could be considered biomarkers but will not be included in this review. On the other hand, diagnosing allergy is not usually useful for monitoring asthma although it is of fundamental importance for the interpretation of most biomarkers that are suitable for monitoring. We have therefore included the different approaches for diagnosing and evaluating allergic sensitization in this review.